The difference between B4 and B4-X: 1. B4-X is a dual-mono balanced version. Its left and right channel are amplified by independent components, and power supply, tubes, and op amp are all independent and symmetric. So the degree of sound separation is higher than B4. B4-X adopts 2 groups of independent power supply (+12V and -12V) for 2 op amps, less mutual effects and can drive 300O headphones.
The circuit adopts dual op amp parallel output, with higher output power. B4-X has 3.5mm and 2.5mm, 2 kinds of output interface, suitable for most of balanced and standard headphones. Tube: USA RAYTHEON JAN5899 ×2 Op amp: NE55322 (can be upgraded) Lithium Battery: 12V, 1000mA Charging time: 2-2.5 hours Working time: 4-4.5 hours Output power: 450mW SNR: 105dB Suggest load impedance: 16-300O Output: 2.5 balanced Jack1, 3.5mm Jack 1 Size: about 115 69 23 mm (LWD) (does not include the knob). 1× Headphone amplifier 1× Power supply 1× 3.5mm audio cable 2× Band. Software sales are not refundable. This item is in the category "Consumer Electronics\TV, Video & Home Audio\Home Audio\Receivers & Amplifiers\Amplifiers & Preamps". The seller is "george201818" and is located in this country: CN.This item can be shipped worldwide.